I don't think the A77 needs to be replaced this year, here is why.

Canon most certainly WILL release an updated 7D this year - and it's a pretty easy guess that it will be a significant improvement; Nikon HAS released the 7100. Sony has gotten a boost to Alpha only via the NEX part of the line; the A-mount needs to bring positive attention to itself and a "flagship" is one of the main ways to do so. I hardly ever use my A77 because I don't do a lot of fair-weather shooting; my A99 serves that purpose better, but often my Canon 1D.4 does even better (I'm not talking about DR, but about the performance: never any lag, quicker AF locks, better buffer system, almost laughs at any type of weather). I think Sony's attention to NEX was the right move, but they've got to do for A-mount what they did for NEX (I wasn't one of the ones in love with the A7/R concept; it was clear that these would be niche-use bodies), otherwise A-mount will continue to be a drain financially. They've got to come out strong, and not just via marketing hype; they have to get tangibly better.